Apparatus and process for reducing waste organic materials into clean, sterilized powder, meal or flakes

ABSTRACT

An apparatus and process are provided for rapidly and efficiently processing raw organic material into high quality clean, sterilized powder, meal or flakes. Means are provided for dividing the organic material into particles of substantially uniform size and for feeding the particles into milling and heating means. The particles are then simultaneously milled and heated by applying centrifugal forces to grind the material, and controlled laminar flow of hot air or gases to dry the material until the desired powder meal or flakes are produced. The powder, meal or flakes are then withdrawn from the milling and heating means and heated air and steam are separated therefrom.

United States Patent [191 Poggie n11 3,823,877 July 16, 1974 APPARATUS AND PROCESS FOR REDUCING WASTE ORGANIC MATERIALS INTO CLEAN, STERILIZED POWDER, MEAL OR FLAKES 3,682,399 8/1972 Kaspar et al 241/54 Primary Examiner-Granville Y. Custer, Jr. Attorney, Agent, or FirmMeyer A. Baskin, Esq.

[76] Inventor: Joseph L. Poggie, 815 Iris Ln., Vero [57] ABSTRACT Beach 32960 An apparatus andprocess are provided for rapidly and [22] Filed: June 5, 1972 efficiently processing raw organic material into high quality clean, sterilized powder, meal or flakes. Means [21] Appl' 259869 are provided for dividing the organic material into particles of substantially uniform size and for feeding [52] US. Cl. 241/19, 241 /24, 241 /54 the particles into milling and heating means. The par- [51] Int. Cl. B02c 21/00 i les re th n simultaneously milled and heated by [58] Field of Search 241/47, 54, 55, 56, 57, app y ng e ug forces to grind e e an 241/58, 18, 19, 24 controlled laminar flow of hot air or gases to dry the material until the desired powder meal or flakes are [56] References Cited produced. The powder, meal or flakes are then with- UNITED STATES PATENTS drawn from the milling and heating means and heated 696 396 4/1902 Avery 24157 air and steam are separated therefrom. 3,452:937- 7/1969 Haskins et al. 241/47 8 Claims, 4 Drawing Figures FEED 1ST 2410 MOT??? CYCLONE CYCLONE I a l l l l i 52%??? I MILL I TEMF? DEHYDRfiTOF? SEA/50R THROTFLE l-f:/:Fulwnce MEET BURNER lzxmusrER 5-225 I l 1 l I l J (M/ EXHAUSTERI (DOL/NG rm; 1 TEME M0705 Ma PATENIEn JUL I 6 m4 SHEET 1 0F 2 1 APPARATUS AND PROCESS FOR REDUCING WASTE. ORGANIC MATERIALS INTO CLEAN,

STERILIZED POWDER, MEAL R FLAKES This invention is related to co-pending applications, Ser. No. 98,005, filed Dec. 14, 1970, now abandoned, and Ser. No. 158,497. filed June 30, 1971, now U.S. Pat. No. 3,761,024.

STATE OF THE PRlORART The present state of the art for mill-dehydrators provides four basic concepts. The most commonly used arrangement is a long tube that is heated and rotated simultaneously. The raw material is introduced at one end and is heated and ground while it travels the length of the tube. The material ultimately emerges from the opposite end as a roughly ground powder. This rough powder is then ground to the desired size in a conventional hammer-mill.

The second most commonly used process grinds the raw material to medium sized pieces. These medium sized pieces are then heated and ground to a pulp, and the pulp is finally mixed with hot air to reduce itto a powder.

The third and fourth prior art apparatus and process consists of a high speed, hightemperature milldehyd-rator in which the grinding and drying are accomplished quickly and simultaneously.

of time required to process the raw material to the fmished product is also substantial so that the yield of the finished product, per unit time, from these prior art devices is relatively small.

ln the most commonly used prior art device, wherein a long'tube is utilized, the destruction of vital elements in the raw material is brought aboutbecause the rotation tube or drum contains pieces of material ranging in size from large chunks of raw material to small grains of finished dry material. As a result, the raw material presents a wide range of volume-area ratios so that it is impossible to provide optimum drying conditions. The heat adsorption rate of the large pieces is limited by the low area-volume ratio, and the small particles are rapidly'dried because of their high area-volume ratio. Y

The heat transfer rate to the larger pieces can only be shown that the processing time for most material is sev eral hours.

This long processing time results in the destruction of heat sensitive protein, vitamins and nitrates in addition to general burning of the material and may often actually encourage bacteria growth.

Thesecond most commonly used prior art method is a partially successful attempt to overcome the objectional features of the rotating drum arrangement. By separating the grinding and drying operations, charring is largely eliminated; however, the heat transfer rate is low because the air velocity relative to the material is extremely low even though the absolute velocity of the heated air is high. The net 'result isthat the machine is very large, the processing time long, and the heatsensitive protein is destroyed because of the long time exposure to heat. The efficiency of this method is also extremely low.

The third prior art apparatus and process, in which the grinding and drying are accomplished simultaneously in a high speed, high temperature milldehydrator consisting of an apparatus in which the hot, dry air and the material to be processed are admitted to the mill in an axial direction at one end and the finished powder or meal, vapors and air withdrawn through an annular opening around the shaft at the other end'of the mill. The materialis ground and dried in the mill under conditions of extreme turbulance. The

turbulance, in combination withthe action of the exhaust fan at the mill exit provides the means of separating the finished product from the unfinished material so that the finished product may be withdrawn from the mill.

The disadvantages of this process and apparatus are:

A.,A temperature gradient is established alongthe axis of the mill, the temperature of the mixture being" high at the inlet end and low at-the outlet end. This lowering of the temperature as the material travels to the;

mill outlet increases the time that the material mustremain in the mill, thus reducing the mill capacity.

B. The turbulent air flow in the mill results in increased power required to movethe air.

, C. The turbulent air conditions in the mill do not permit complete control of the process, especially the separation of the finished product.

The fourth prior art device is shown my copending application, of which this is a cOntinuatiOn inincreased by increasing the temperature of the air or of the drum surface or by increasing the air velocity, thus sirable and destroys the vital elements sought to be re- A tained in the finished product. Similarly, increasing the heat transfer coefficient by increasing the velocity requires that the air volume also be increasedwith attendant loss of efficiency.

Even with conditions at the optimum obtainable with,

this long rotating tube arrangement, experience has part. This 'device and process provides for the entrance of the hot air into the mill in a radialdirection, through a radially extending port in the mill side. The port extends the full length of the mill, parallel to the axis of the shaft. The peripheral dimension of the port was so limited, and the port so designed that the incoming air was directed essentially at the shaft Thehot air entering the mill applied an. aerodynamic force directed radiallyinward on each particle of'ma'terial that passed the inlet port. The aerodynamic force was substantially equal and opposite to the centrifugal forces generated by therotating moist 0r unfinished particles and greater than thec'entrifugal force generated by the dry, finished'particles. The balanced forces on the unfinished material prevented the high density unfinished materialfrom being forced back into the hot airinlet and thus prevented build-up of material in the hot air passage,

, and also prevented any fires that would occur if a buildup were allowed to exist.

When the material in the mill reached the desired size and degree of dryness, the centrifugal force was reduced, by virtue of the loss of moisture, to the point where the aerodynamic force exceeded the centrifugal force and the finished product moved inward toward the center of the mill and axially toward and out the annularexit.

The disadvantages inherent in this device are:

A. The magnitude of the aerodynamic forces that can be generated by the hot air on the particles passing the hot air entrance to the mill are limited by practical considerations such as air density and air inlet velocity. The air inlet velocity, in turn, is limited by the pressure gradient that can be generated by an exhaust fan regardless of size or power input. I

B. Limitations of the magnitude of the aerodynamic forces also place a corresponding limitation on the centrifugal forces that can be tolerated in the mill. Consequently, the mill size, speed and power inputsare limited because the device cannot function if the centrifugal forces are-so great that it is impossible to create aerodynamic forces to overcome them.

BACKGROUND OF THE PRESENT INVENTION also makes possible the removal, by vaporization or thermal destruction, of many undesired elements or compounds in the original unprocessed material so that the finished product is not contaminated and may be used in the production of foods and medicinal products.

By use of the process and apparatus of the present invention, anyorganic .waste material can be recycled back into the ecological system as food or fertilizer,

thereby preventing pollution of water, ground and air that normally occurs when these waste materials are disposed of by other means.

It is a principal object of the present invention to provide an improved apparatus for optimizing the drying and grinding process for converting any material, especially organic material into clean, dry, sterilized powder, meal or flakes.

Another object is to-provide a process and apparatus for processing organic material while preventing deterioration of vital elements in the material.

A further object of this invention is the provision of aprocess and apparatus for processing organic material in a'single, high speed operation.

Still another objectis to provide apparatus for processing organic material into clean, dry, sterilized powder high in protein, low in ash, high in digestibility,- and low in bacteria count. I

Yet another object is to provide an apparatus for very quickly and efficiently processing organic material into clean, sterilized powder, meal or flakes.

Another object is to provide an apparatus for processing material in which the apparatus has no limitations as to size or capacity.

A still further object of the present invention is to provide a new and improved means of simultaneously milling and drying materials by supplying an essentially laminar flow of hot air throughthe mill-dehydrator. The laminar flow results in a continuous, orderly replacement of the used drying medium in the mill by new, hot, dry medium from the furnace so that there is a minimum of mixing of the incoming and existing drying medium.

Another principal object of thisinvention is to provide a tangential inlet'for the air into the mill whereby the main fan must overcome'the mill fan effect only, .but not the centrifugal force on the particles.

By the reduction or elimination of turbulence and the elimination of the requirement to balance centrifugal and aerodynamic forces, efficiency is increased, the process is controllable, and machine design and operation simplified.

Preferably, the mill-dehydrator includes a furnace having an interior portion in fluid communication with the heating and milling means for enabling heated air to pass from the interior of the furnace into the milling and heating means to heat the material therein. Additionally, it is preferred that the apparatus includes control means connected for sensing the temperature. of air, steam, and the powder, meal or flakes exiting from the withdrawing means, and for controlling operation of the feed means and of the furnace.

The milling and heating means preferably comprise:

a housing having an inlet for receiving heated air, a feed inlet for receiving material from the feed means, and an outlet for exhausting powder, meal, or flakes from the housing; a shaft positioned within the housing for rotation about its own axis; and a plurality of instruments, such as knives or hammers, fastened to the shaft for acting upon material within the housing inthe presence of heated air from the furnace to produce powder, meal or flakes within the milling and heating means, It is also preferable that the milling and heating means be constructed so that the outlet of the housing forms an annular opening around one end of the shaft and wherein the feed inlet of the housing is located adjacent to the opposite end of the shaft. 7 The improvement of this invention is concerned with the design and positioning of the hot air inlet, which is such as to permit heated air to enter the interior or the housing essentially .tangent to, and in the same direction as the rotating layer of air and particles at or near the outer tips of the rotating hammers or knives.

. Thus, this invention provides for a highly efficient process and apparatus for processing material into clean, dry, sterilized powder, meal or flakes in an extremely short period of time.- 55 I BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing one general arrangement of a system in which the present invention may be utilized;

FIG. 2 isa diagrammatic plan view, partially in section, of the milling and heating means of the present invention;

FIG. 3 is a vertical sectional view taken along the line 3-3 in-FIG. 2; and

FIG. 4 is a diagrammatic sectional view similar to FIG. 3, illustrating the flow path of the air and material entering and leaving the mill.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION With reference to the drawings, wherein like reference characters designate like or corresponding parts throughout the various views, FIG. 1 is a schematic representation of a typical complete system in which the present invention is incorporated.

The waste materials are disposed in a hopper and, in accordance with the state of the art, are conveyed into a motor driven feed means where the waste materials are divided into particles of substantially uniform size. Preprocessing may include heating and pressing the materials enough to break down fatty tissues and to remove excess oils and water.

The substantially uniformly sized pieces of waste ma- 1 terial are metered'by the feed means into the milldehydrator of thepresent invention. A furnace employing conventional burner means supplies heated air to Y the mill-dehydrator which is driven by a variable speed motor, designated mill motor in FIG. 1.

After the waste material in the mill-dehydrator has been converted into the desired powder, meal or flakes,

' the material is aerodynamically conveyed by the motor -to separate the cooled powder from the air to deliver the final, finished productto an appropriate outlet.

If desired, a fixed speed exhauster motor may be provided for the exhauster fan, and the air flow between the mill-dehydrator and the exhauster fan may be controlled by a throttle in the air duct therebetween.

In accordance with standard procedure, control means are included in the system for sensing the temperature of air, steam, and the powder, meal or flakes existing from the exhauster, for controlling operation of the feed means and-of the furnace burner. As illustrated, the control means include a temperature sensor or thermocouple located at the outlet of the exhauster for sensing the temperature of the material, air and steam passing that point and another temperature sensor for sensing the temperature of the hot gasentering the mill-dehydrator.

A signal from the exhauster sensor is conducted to the temperature control which compares the signal to predetermined set values in a conventional manner and determines when the feed motor is to be energized and,

also, when the fuel flow rate-is to be increased or decreased. 1

A signal from the furnace hot gas sensor to the tem perature control adjusts the fuel pressure in the burner to compensate for changing ambient conditions.

With reference to FIGS. 2 and 3, the mill-dehydrator of the present invention includes a generally annular,

cylindrical housing 10, having opposed end walls 12' and 14. Adrive shaft 16 axially spans the housing and is rotatably journaled in bearings 18 and 20; the

variable speed motor FIG. 1, drives the shaft 16. Fixed to andextending generally radially outwardly from the shaft 16 are a plurality of instruments 22, such as knives or hammers. As-indicated by the dot-dash. lines 24, the instruments extend-in a spaced relation substantially along; the length of the drive shaft 16, within the housing 10.

A first inlet 26 is provided in one end of the housing 10 to deliver the pre-processed material from the feed means into the annular chamber 28 provided within the housing 10; the inlet may be provided anywhere around the circumference of the housing 10.

A second inlet 30, as best illustrated in FIG. 2, is positioned to deliver the heated air from the furnace tangentially into the chamber 28 with respect to the extended ends of the instruments 22 and in the direction of rotation thereof.

An outlet 32, in the form of an annular opening around the end portion of the drive shaft 11, is preferably provided at the opposed end of the housing relative to the material feed inlet 26.

In operation of the process and apparatus of the present invention, unprocessed waste material is loaded into the hopper and is conveyed by gravity or other conventional means therefrom into the feed means where the material ispressed, cut and'broken up into by metering action of the feed means so that the rate at which the material .is fed through the first inlet 26 into the mill-dehydrator chamber 28 can be controlled by adjusting the variable speed feed motor.

As the particles P of material enter the chamber 28, they are struck by. the rapidly rotating instruments 22,

such as knives. or hammers, and the particles P are whirled around the inside of the chamber 28. Because of the, centrifugal force generated by this rotation, the

particles are thrown against the chamber wall where most of the momentum of the particles P is dissipated. This momentum is dissipated in four primary ways:

first, it is converted into destructive energy that frac-.

tures the raw particles and grinds them into increasingly smaller particles. The fracture of the raw particles separates the dry outer layers of material from the wet cores so that the dry material can be carried out of the mill by the air stream 36. Second, a portion of the momentum is converted into heat. Third, some particles rebound off of the wall of the chamber 28 and back into the path of the instruments 22 where they are again thrown against the chamber wall. Fourth, the particles which have lost most of their momentum fall to -the bottom of the chamber 28 where they are picked up by the instruments 22 and again thrown against the walls of the chamber 28.

Asthe rapidly rotating unfinished particles P, carried by the instruments 22, pass through the more slowly rotating mass of hot air in the mill, they follow an in and out, zigzag path 38,, which is the result of the inward and outward motions combined with the circumferential velocity aroun'd'the inside of the chamber 28.

When the particles P pass the hot air inlet 30, the magnitude of the centrifugal force on each particle determines the path the particle will follow. High density, unfinished particles along the circumferential path 38 will continue on the same course while completed particles P1 remain with the laminar flow air stream and leave the mill with the expended air and water vapor stream 36.

Because the hot air 40 from the furnace enters the mill tangentially and travels in the same direction as the aerodynamic forces on the revolving waste materials as it passes-the hot air inlet 30. This is a very important factor regardless of whether the air flow is generated by Any particles P passing the'tangential inlet 30 in the general direction indicated by the arrows 42 have two forces acting on them, centrifugal force and aerodynamic force. These two forces are not in direct opposition in the mill-dehydrator of the present invention as they are when the hot air inlet is disposed radially to the drive shaft 16. Instead, they are generally at less than right angles to each other so that the resultant force causes the particles to follow the path of the arrows 38 and 42 instead of an upstream path into the hot air inlet 30.

This results in less power being required to move the air in the device since it is not necessary to create an aerodynamic force great enough to balance the centrifugal force. Less fuel is'therefore required as the only air requirement is that called for in the thermodynamic process. More mechanical, grinding energy can be put intothe-mill-dehydrator since the centrifugal forces therein are no longer limited bythe aerodynamic forces.

In actual operation I have found a very satisfactory range of temperature to be 1,200 to l,300 F: for the mill inlet temperature. Higher temperature might be used in a larger mill with increased efficiency and capacity. This is for use on organic waste product such as fish scraps from commercial processing of crabs, fish, shrimp, etc., as well as organic waste products from other food processing operations such as vegetables, fruit-pits and animal manure. The treatment of such organic material is the preferred application of my inventron.

An outlet temperature from the mill of about 200 to 500 F., depending on moisture content of finished product desired, is preferred. Lower outlet temperatures produce a higher moisture content of the finished product.

Air velocity through the mill is a function of temperature desired and mill speed. With a 24 inch diameter mill at 3,000 r.p.m., an inlet velocity of 200 ft./min. to 500 ftjmin. has given goodresults with temperatures in the above ranges.

What is claimed is:

1. An apparatus for processing organic waste material comprising; r t

A. a mill dehydrator having,

1. a elongated cylinder housing providing,

' a. a first inlet for supplying the waste material to said annular chamber from said feed conduit, tangential to 'said housing, g

b. a second inlet for supplying hot gases tangentially to said cylindrical chamber to dehydrate outer ends closely adjacent to the outer wall of said chamber;-

2. exhauster means for withdrawing the hot gases, and reduced material from saidchamber through an outlet surrounding said axially extending'shaft said outlet being of substantially smaller diameter than said cylinder housing.

2. An apparatus as defined in claim 1 wherein said hot air is conducted to said mill-dehydrator by a hot air conduit opening tangentially into said annular chamber'.

3. An apparatus, as defined in claim 1, wherein said first inlet is located adjacent one end of said chamber and said second inlet extends substantiallyalong the length of said chamber, and said exhauster means is located at the opposite end of said chamber from said first inlet.

4. An apparatus as defined in claim 1, wherein said 1 hot gases enter said chamber tangentially, moving in same direction as the motion of said plurality of instruments.

' 5. An apparatus, as defined in claim' 4, werein said outlet is in the form'of an annular opening, co-axial with said drive shaft, in the end of the housing opposite to said first inlet.

6. A process for converting organic materials into a clean, sterile powder, meal or flakes, comprised of the following steps: I

A. Breaking up the material into relatively uniformly sized particles;

B. Introducing the materials into a mill-dehydrator;

C. Applying'rotational velocities to the material in the mill-dehydrator in a predetermined direction by means of a plurality of rotating instruments extending radially outwardly from a driven shaft;

D. Simultaneously with said rotational movement,

introducing hot gases tangentially into said milldehydrator to dry the material whereby the mass of each particle is reduced to powder, meal or flakes by the combination of said rotational velocities and hot gases.

7. The process, as defined in claim 6, wherein the fan effect of the rotating instruments is overcome by an exhaust fan, relative to the lightweight powder, meal or flakes produced in the mill-dehydrator, to remove same from said mill-dehydrator through an outlet provided therein. 8. The process, as defined in claim 7,wher ein the expanded gases and the finished powder, meal or flakes are caused to spiral toward the .center of the milldehydrator and out said outlet while the wet, unfinished particles continue to rotate in the mill-dehydrator until they reach the desired state of dryness. 

2. exhauster means for withdrawing the hot gases, and reduced material from said chamber through an outlet surrounding said axially extending shaft said outlet being of substantially smaller diameter than said cylinder housing.
 2. An apparatus as defined in claim 1 wherein said hot air is conducted to said mill-dehydrator by a hot air conduit opening tangentially into said annular chamber.
 3. An apparatus, as defined in claim 1, wherein said first inlet is located adjacent one end of said chamber and said second inlet extends substantially along the length of said chamber, and said exhauster means is located at the opposite end of said chamber from said first inlet.
 4. An apparatus as defined in claim 1, wherein said hot gases enter said chamber tangentially, moving in same direction as the motion of said plurality of instruments.
 5. An apparatus, as defined in claim 4, werein said outlet is in the form of an annular opening, co-axial with said drive shaft, in the end of the housing opposite to said first inlet.
 6. A process for converting organic materials into a clean, sterile powder, meal or flakes, comprised of the following steps: A. Breaking up the material into relatively uniformly sized particles; B. Introducing the materials into a mill-dehydrator; C. Applying rotational velocities to the material in the mill-dehydrator in a predetermined direction by means of a plurality of rotating instruments extending radially outwardly from a driven shaft; D. Simultaneously with said rotational movement, introducing hot gases tangentially into said mill-dehydrator to dry the material whereby the mass of each particle is reduced to powder, meal or flakes by the combination of said rotational velocities and hot gases.
 7. The process, as defined in claim 6, wherein the fan effect of the rotating instruments is overcome by an exhaust fan, relative to the lightweight powder, meal or flakes produced in the mill-dehydrator, to remove same from said mill-dehydrator through an outlet provided therein.
 8. The process, as defined in claim 7, wherein the expanded gases and the finished powder, meal or flakes are caused to spiral toward the center of the mill-dehydrator and out said outlet while the wet, unfinished particles continue to rotate in the mill-dehydrator until they reach the desired state of dryness. 